Arrangement in motor driven reciprocating percussion machines with exchangeable tools



May 28, 1968 A. BERGMAN 3,385,379 ARRANGEMENT IN MOTOR DRIVEN RECIPROCATING PERCUSSION MACHINES WITH EXCHANGEABLE TOOLS Filed'Feb. 16, 1967 2 Sheets-Sheet l .FiG.1

INVEN TOR. GUST/4V Awzxrflaeanmw May 28, 1968 G. A. BERGMAN 3,385,379

ARRANGEMENT IN MOTOR DRIVEN RECIPROCATING PERCUSSION MACHINES WITH EXCHANGEABLE TOOLS Fil ed Feb. 16, 1967 2 Sheets-Sheet 2 FIG.5 7* 2 31. 2 32 4.9 v 1.5 k 30 H LO H1 L7 FIG.6

INVENTOR. Gusmuflwaerfiaea4uw United States Patent "ice 3,385,379 ARRANGEMENT IN MOTOR DRIVEN RECIP ROCATING PERCUSSION MACHINES WITH EXCHANGEABLE TOOLS Gustav Albert Bergman, Baldersvagcn 20, Danderyd, Sweden Filed Feb. 16, 1967, Ser. No. 616,705 6 Claims. (Cl. 173-48) ABSTRACT OF THE DISCLOSURE A mechanism in percussion machines comprising a shaft with catches for cooperation with alternatively a blocking sleeve in a tool-rotating mechanism and a tool holder whereby to adapt the machinealternat-ively to boring operation and poking operation, respectively. In the boring position the blocking sleeve is prevented from rotation whereby the tool-rotating mechanism becomes effective, and in the poking position the blocking sleeve is disengaged and said mechanism is idle, whereby no rotary movement is imparted to the tool holder and the tool.

This invention relates to motor driven reciprocating percussion machines adapted to operate with different types of tools, such as drilling tools and poking tools. The tool is insertable into a tool holder of the machine which tool holder during drilling operation is rotating and during for instance poking or breaking or mining operation should be stationary so that the tool will not rotate. In such machines rotation of the drilling tool is effected by a revolving mechanism which includes a freewheel clutch having clutch members provided between a revolving sleeve and a blocking sleeve.

The object of the invention is to provide an arrangement which permits convenient exchange of tools and corresponding adjustment of the machine without the necessity of removing other parts of the machine.

To this end the arrangement according to the invention is characterized in its broadest aspect by the fact that the blocking sleeve is rotatable but lockable by means of a locking device which is accessible from the outside of the machine and adjustable between different positions, namely, a first position or drilling position in which it locks the blocking sleeve against rotation, and another position or poking position in which said device releases the blocking sleeve and locks the tool against rotation. Usually the revolving mechanism is actuated by the reciprocating movement of the percussion hammer which cooperates with the tool holder for imparting motion thereto. According to a simple embodiment the locking device comprises a shaft provided with catches which in one angular position of the shaft are in engagement with recesses in the blocking sleeve and in another position are disengaged from said recesses and in engagement with recesses in the tool holder. Due to this arrangement shifting from drilling operation to poking operation and vice versa can be effected in a most simple manner by turning the locking shaft.

Machines of the kind in consideration are provided with means for admitting air under pressure into the bore hole for cleaning this hole from stone dust formed during the drilling operation. No such blowing air is required during poking operation. It is therefore advantageous to combine the device for shifting from drilling to poking operation and vice versa with means for simultaneous switching of the blowing air. For this purpose the locking device may be combined with a valve which in the drilling position closes a connection between the blowing-air duct of the machine and the ambient air so 3,385,379 Patented May 28, 1968 that blowing air is admitted to the bore hole for cleaning said hole, whereas the valve opens said connection in the poking position. According to a simple construction the valve forms part of the locking shaft. The locking device may further be adapted to be set in a neutral position in which the revolving mechanism is inoperative and the tool holder is disengaged. In this case it is possible to start the machine for instance with an inserted drilling tool without the drilling tool being rotated, and the machine can idle without inconvenience.

An example of the application of the invention is described hereinbelow with reference to the annexed drawings in which FIG. 1 is a longitudinal sectional view of the lower portion of a machine arranged in accordance with the invention,

FIG. 2 is a cross-sectional view of the part of the machine where the locking device is provided,

'FIG. 3 is a plan view of said part of the machine,

FIG. 4 is a fragmentary sectional view taken along the line 44 in FIG. 2,

FIG. 5 is par-t of a longitudinal sectional view of a modified embodiment, and

FIG. 6 is a cross-sectional view taken along the line 66 in FIG. 5.

Referring to FIG. 1 which illustrates the lower part of the machine, a percussion hammer comprises a reduced-diamete-r piston portion 10 which in a conventional manner operates in one end of the cylinder of an internal combustion engine, and a larger piston portion 12 which is movable in a hammer cylinder 14. A guide member 16 for the piston rod 18 of the hammer forms an end wall of the hammer cylinder .14 and fits at its circumference in a part 20 of the housing of the machine. Inserted between the lower end of the hammer guide 16 and a blocking sleeve 22 forming part of a revolving mechanism is a bearing 24' preferably in the form of a needle hearing. The lower part of the blocking sleeve 22 is mounted on a tool holder 24 by means of a bearing 26 which preferably also consists of a needle bearing. The tool holder 24 is mounted in the lower part of the housing 20 by means of a bushing 28 and is internally devised to receive the top end of the shank of a tool, nsually a drilling tool or a poking tool, the shank of which is actuated by the lower end of the piston rod 18 of the hammer during the reciprocating movement of the hammer.-

A drilling tool inserted in the tool holder has not only to be subjected to impacts from the hammer but has also to be rotated, whereas a poking or breaking tool has to be subjected to impacts only without being rotated. In other words the revolving mechanism of the machine should be operative during drilling and inoperative during poking, breaking or mining. The revolving mechanism acts in a manner known per se such that a revolving sleeve 30 secured to the top end of the tool holder 24 will be stepwise advanced in cooperation with clutch rollers 32 and internal lands 34 in the revolving sleeve and helical grooves 36 in the piston rod, the forces of reaction and the locking action on the clutch rollers 32 being effected by the surrounding blocking sleeve 22. The revolving motion is transmitted to the tool holder by means of lands 38 which are provided on the inside of the holder and are in engagement with axial grooves 40 in the piston rod 18.

As distinguished from conventional constructions in which the blocking sleeve is stationary in the housing of the machine, the blocking sleeve illustrated is rotatable by means of the revolving sleeve 30* and the clutch rollers 32 during reciprocating movement of the hammer unless rotation of the blocking sleeve is prevented. This is effected by means of a locking device which consists of a shaft 42 provided with catches 44 which are adapted to engage grooves 46 in the blocking sleeve 22 or grooves or recesses 48 in the tool holder 24. The ends of the shaft 42 are mounted in a projecting part 50 of the housing 20. One end 52 of the shaft is mounted in a cover 54 and the other end 56 is mounted in a bore 58. The end 52 of the shaft extends outwardly through the cover 54 and carries at its outer end a hand lever 60 which is nonrotatably mounted on the end of the shaft and secured thereto by means of a screw 62. The lever 60 is adapted to be set in three positions, namely, a drilling position B shown in full lines in FIG. 3, a neutral position F at right angles to the drilling position, and a poking or breaking position S which is diametrically opposite to the drilling position. The postions F and S are indicated by chaindotted lines in FIG. 3. The end positions B and S are determined by an abutment 64 on the cover 54 and by radial surfaces 66 and 68 of a projection 70 at the inner end of the lever. In the drilling position B the surface 66 is in contact with the abutment 64, whereas the surface 68 in the position S engages an opposite side of the abutment 64. In order to retain the lever in the various positions, the end 56 of the shaft 42 has correspondingly angularly spaced recesses 72b, 72 and 72s adapted to receive a ball 74 which is acted upon by a spring 76.

The locking device is combined with a valve which in the drilling position closes a connection between the blowing-air duct of the machine and the ambient air so that blowing air is admitted to the bore hole for cleaning said hole, whereas the valve opens said connection in the poking position. Air under pressure is supplied, in a manner not shown, from the compressor of the machine into a duct 78 which has a port in the bore 58. This port faces the end 56 of the shaft 42. The end 56 has a radial bore 80 which communicates with an axial duct 82 which opens into the bore 58 which through a hole 84 communicates with the ambient air.

The mode of operation of the machine described is substantially as follows. With the hand lever 60 in the drilling position shown in FIG. 3 the catches 44 on the shaft 42 are in engagement with the recesses 46 of the blocking sleeve 22 whereas the recesses 48 of the tool holder 24 are disengaged. Consequently, the blocking sleeve 22 is locked against rotation. As the hammer moves upwardly it will be rotated in the hammer guide 16 due to the cooperation of the lands 34 of the revolving sleeve with the oblique grooves 36 in the piston rod 18 of the hammer. The revolving sleeve 30 is prevented from rotation because of the engagement of the clutch rollers 32 with the locked blocking sleeve 22. The turning movement of the hammer is transmitted through the axial grooves and the cooperating lands 38 to the tool holder 24 in which the tool is inserted. In that case the tool is a drilling tool to which a revolving motion is imparted as the hammer moves upwardly. At the downward stroke of the hammer the revolving sleeve 30 rotates in the locked blocking sleeve 22 because the clutch rollers 32 have no locking efiect in that case.

If the lever 60 is shifted from the drilling position B shown in FIG. 3 to the position S with the result that the surface 66 of the projection 70 is removed from the abutment 64 whereas the surface 68 is brought into contact with this abutment the catches 44 will be turned out of engagement with the blocking sleeve 22 and into engagement with the recesses 48 in the tool holder 24 which consequently will be locked. The blocking sleeve 22 is now disengaged and cannot take any forces of reaction from the clutch rollers 32. In other words the rollers 32 cannot lock the revolving sleeve 30 irrespective of the direction of rotation thereof. Nor can the tool holder together with the tool inserted therein be rotated during the reciprocating movement of the hammer. The tool which now is a poking or breaking tool is acted upon exclusively by impacts from the hammer. In order to replace a drilling tool by a poking tool, it is merely necessary to withdraw one tool from the tool holder and to insert the other tool, and no other parts have to be removed.

In the drilling position of the lever 60 the compressed air duct 78 is closed by the end 56 of the shaft 42 so that compressed air cannot escape through the hole 84. This is due to the fact that the radial duct in the end 56 of the shaft faces that wall of the bore 58 which is diametrically opposite to the port of the duct 78. Consequently, blowing air can flow down to the drilling tool for cleaning the bore hole in a conventional manner. If the lever 60 is set in the position S the shaft 42 is turned half a revolution resulting in that the duct 78 is put into communication with the duct 80 and the hole 84 and the ambient air. Blowing air will be discharged into the ambient air and not supplied to the poking tool which does not require such air.

In the neutral position F the catches 44 are disengaged from the recesses 46 of the blocking sleeve 22 as well as from the recesses 48 of the tool holder 24 which means that both the sleeve 22 and the holder 24 are released, this being suitable when the machine is idling.

The invention is not limited to the exemplified embodiment. From the point of view of manufacture it may be advantageous to replace the shaft 42 and the catches 44 by a worm screw and the recesses 46, 48 by the spaces between the threads of a corresponding worm wheel in which case the worm screw threads located on one side of a diametrical plane through the worm screw are to be omitted. Such construction not only facilitates manufacturing but also secures accurate engagement between the locking shaft and the members 22 and 24 which will be maintained in accurately determined positions. This modification is illustrated in FIGS. 5 and 6.

As will be seen from the modified embodiment shown in FIGS. 5 and 6, the catches 44 are in the form of parts 45 of the threads of a worm screw adapted to be put into mesh with corresponding parts 47, 49 of a worm wheel provided on the tool holder 24 and blocking sleeve 22, respectively. FIGS. 5 and 6 also show the oblique or helical lands 34 in the revolving sleeve 30 and the axial lands 38 in the tool holder 24. A retainer ring 25 disposed between the revolving sleeve 30 and the tool holder 24 keeps the clutch rollers 32 in place.

The mode of operation of the modified embodiment shown in FIGS. 5 and 6 is essentially the same as that of the embodiment shown in FIGS. 1 to 4 and is therefore not described.

What I claim is:

1. A motor driven percussion machine, comprising a housing, a reciprocable hammer piston, a tool holder for exchangeable drilling and poking tools, a revolving mechanism for said tool holder including a revolving sleeve adapted to be rotated by the hammer piston, a blocking sleeve and clutch members provided between said sleeves, and a locking device accessible from outside the housing, said blocking sleeve being rotatable but lockable by the locking device, the locking device being adjustable between ditferent positions including a first position or drilling position in which it locks the blocking sleeve against rotation, and another position or poking position in which said device is adapted to release the blocking sleeve and to lock the tool against rotation.

2. Machine as claimed in claim 1, characterized in that the locking device comprises a shaft provided with catches and the blocking sleeve has recesses, said catches being adapted to engage the recesses in one angular position of the shaft and in another position to be disengaged from said recesses and in engagement with recesses in the tool holder.

3. Machine as claimed in claim 2, characterized in that the housing defines a blowing-air duct and that the locking device is combined with a valve adapted in the drilling position to close a connection between said blowing-air duct and the ambient air whereby blowing air is admitted to the bore hole for cleaning said hole,

whereas the valve opens said connection in the poking position.

4. Machine as claimed in claim 3, characterized in that said valve forms part of the locking shaft.

5. Machine as claimed in claim 1, characterized by means to keep the locking device in a neutral position in which the revolving mechanism is inoperative and the tool holder is disengaged.

6. Machine as claimed in claim 1, characterized in that the locking device comprises a worm screw which in the locking positions is adapted to mesh with correspending worm wheel threads on the blocking sleeve and tool holder. I

References Cited UNITED STATES PATENTS 2,013,744 9/1935 Curtis 173-l09 X 2,056,293 10/1936 Rasch l73109 X 2,108,989 2/1938 Mack 173-408 X 3,056,390 10/1962 Nyholm l73l09 I 3,161,241 12/1964 Allen 17347 NILE C. BYERS, JR., Primary Examiner. 

